Conventionally, digital cameras, each of which converts an image signal sensed by an image sensing element such as a CCD or the like into a digital signal, processes that digital signal to obtain a digital video signal including luminance and color difference signal components, applies compression processing such as JPEG to the digital video signal, and records the compressed signal on a recording medium, have been developed. The resolution of an image sensing element in such digital camera is increasing, and some elements have several million pixels and more than ten-million pixels.
Meanwhile, many cameras have a function of recording a moving image by reading signals at high speed from the image sensing element while skipping horizontal and vertical lines and the like. More specifically, recent digital cameras have a still image sensing mode for performing still image sensing processing described above, and a moving image sensing mode for performing moving image sensing processing, and these image sensing modes are switched by a user's operation.
In recent years, it has become possible to sense still images during moving image recording (Japanese Patent Laid-Open No. 2004-201282). A technique according to this reference describes a method of solving a problem that a moving image compressed data file is divided into two files to have a still image between them in moving image sensing interrupted by still image sensing when a still image is sensed during moving image recording. More specifically, one frame immediately before a still image sensing period is used as a substitute frame, which is continuously stored in a moving image file only during the still image sensing period, thus preventing a moving image file from being divided. Furthermore, this reference also discloses a technique for synchronizing the start timing required to restart moving image sensing processing by image sensing means after completion of still image sensing to a moving image frame sensing period in moving image sensing processing before the moving image sensing processing is interrupted.
Also, a technique using special image data or non-image frame as a substitute frame which substitutes an omitted moving image frame is known (Japanese Patent Laid-Open No. 2003-8948).
However, in the aforementioned prior art, as for display of a non-image frame (blackout image) or a substitute frame (stop-motion image) immediately before and after a moving image or from a still image, a substitute frame is inserted so as not to interrupt the moving image display. A moving image which has motion when it is sensed actually is unnaturally displayed during the still image sensing period. That is, when a sensed moving image is played back, an awkward moving image is displayed during the still image sensing period in a moving image unlike normal moving image display, thus making the user feel unnatural.